chore(requirements): update ndg-httpsclient to 0.4.1

See https://github.com/cedadev/ndg_httpsclient/#041
and cedadev/ndg_httpsclient@v0.4.0...0.4.1

Author: mboersma

rootfs/requirements.txt

@@ -8,7 +8,7 @@ docker-py==1.8.1
 gunicorn==19.6.0
 jsonfield==1.0.3
 morph==0.1.2
-ndg-httpsclient==0.4.0
+ndg-httpsclient==0.4.1
 psycopg2==2.6.1
 pyOpenSSL==16.0.0
 pytz==2016.4